Date: Wed, 18 Nov 2009 18:38:28 +0200 From: Alexander Motin <mav@FreeBSD.org> To: Norikatsu Shigemura <nork@FreeBSD.org> Cc: freebsd-current@FreeBSD.org Subject: Re: How do I use NCQ of Intel X25-E(SSD) on ahci(4)? Message-ID: <4B042304.8060807@FreeBSD.org> In-Reply-To: <20091119004651.7432a6e4.nork@FreeBSD.org> References: <20091119004651.7432a6e4.nork@FreeBSD.org>
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Hi. Norikatsu Shigemura wrote: > I have a Intel 64GB SSD(X25-E) and a Western Digital Caviar Green > 1TB HDD (WD10EADS), and use them on ahci(4). ahci(4) can use NCQ > of WD10EADS, but doesn't use NCQ of X25-E. > > # camcontrol identify ada0 > pass0: <SSDSA2SH064G1GC INTEL 045C8790> ATA/ATAPI-7 SATA 2.x device > pass0: 300.000MB/s transfers > > Native Command Queuing (NCQ) yes 30/0x1E Here is the reason ^^^ This drive support less tags (31) then your AHCI controller does (32). Support for such case is not implemented yet. As temporary solution you may limit controller to use only 31 tag, then NCQ will be used. All you need is to go to ahci.c and change line ch->numslots = ...; to ch->numslots = min(31, ...); -- Alexander Motin
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